Optical networks rely on switches, modulators and data selectors in order to reliably distribute signals via extensive and ramified systems. Electrical switches, associated with conversion of the optical signal into an electrical signal and reconversion, require a not-inconsiderable amount of electronic hardware and are furthermore coupled with an appreciable power consumption. For switching optical data lines, micromechanical structures have been used for some time and enable signals to be distributed at a purely optical level. Modulation frequencies of about 1 Mb/s initially were achieved thereby, with these frequencies since increased through structural improvements.
Conventional optical switches typically use a simple data line with a shutter that interrupts the optical path, or a moveable mirror that either reflects a beam to a connection piece of an optical waveguide or projects the beam onto an optically inactive area. These switches generally comprise micromechanical systems that modulate the light beam by capacitive deflection of a moveable structure. Another conventional approach is a micromechanical interference filter used as an optical switch.
These conventional solutions suffer from drawbacks. Most are structurally complex and therefore expensive to manufacture. Some, such as the shutter approach, have disadvantageous structural requirements, such as a movable part that covers a distance of about 10 μm or more in order to operate reliably. In the case of interference filters, such structures are difficult to integrate well into an application-specific integrated circuit (ASIC) or peripheral electronics.
Therefore, there is a need for improved optical switching devices.